// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_SELFADJOINT_PRODUCT_H
#define EIGEN_SELFADJOINT_PRODUCT_H

/**********************************************************************
* This file implements a self adjoint product: C += A A^T updating only
* half of the selfadjoint matrix C.
* It corresponds to the level 3 SYRK and level 2 SYR Blas routines.
**********************************************************************/

namespace Eigen {

template <typename Scalar, typename Index, int UpLo, bool ConjLhs, bool ConjRhs>
struct selfadjoint_rank1_update<Scalar, Index, ColMajor, UpLo, ConjLhs, ConjRhs>
{
    static void run(Index size, Scalar* mat, Index stride, const Scalar* vecX, const Scalar* vecY, const Scalar& alpha)
    {
        internal::conj_if<ConjRhs> cj;
        typedef Map<const Matrix<Scalar, Dynamic, 1>> OtherMap;
        typedef typename internal::conditional<ConjLhs, typename OtherMap::ConjugateReturnType, const OtherMap&>::type ConjLhsType;
        for (Index i = 0; i < size; ++i)
        {
            Map<Matrix<Scalar, Dynamic, 1>>(mat + stride * i + (UpLo == Lower ? i : 0), (UpLo == Lower ? size - i : (i + 1))) +=
                (alpha * cj(vecY[i])) * ConjLhsType(OtherMap(vecX + (UpLo == Lower ? i : 0), UpLo == Lower ? size - i : (i + 1)));
        }
    }
};

template <typename Scalar, typename Index, int UpLo, bool ConjLhs, bool ConjRhs>
struct selfadjoint_rank1_update<Scalar, Index, RowMajor, UpLo, ConjLhs, ConjRhs>
{
    static void run(Index size, Scalar* mat, Index stride, const Scalar* vecX, const Scalar* vecY, const Scalar& alpha)
    {
        selfadjoint_rank1_update<Scalar, Index, ColMajor, UpLo == Lower ? Upper : Lower, ConjRhs, ConjLhs>::run(size, mat, stride, vecY, vecX, alpha);
    }
};

template <typename MatrixType, typename OtherType, int UpLo, bool OtherIsVector = OtherType::IsVectorAtCompileTime> struct selfadjoint_product_selector;

template <typename MatrixType, typename OtherType, int UpLo> struct selfadjoint_product_selector<MatrixType, OtherType, UpLo, true>
{
    static void run(MatrixType& mat, const OtherType& other, const typename MatrixType::Scalar& alpha)
    {
        typedef typename MatrixType::Scalar Scalar;
        typedef internal::blas_traits<OtherType> OtherBlasTraits;
        typedef typename OtherBlasTraits::DirectLinearAccessType ActualOtherType;
        typedef typename internal::remove_all<ActualOtherType>::type _ActualOtherType;
        typename internal::add_const_on_value_type<ActualOtherType>::type actualOther = OtherBlasTraits::extract(other.derived());

        Scalar actualAlpha = alpha * OtherBlasTraits::extractScalarFactor(other.derived());

        enum
        {
            StorageOrder = (internal::traits<MatrixType>::Flags & RowMajorBit) ? RowMajor : ColMajor,
            UseOtherDirectly = _ActualOtherType::InnerStrideAtCompileTime == 1
        };
        internal::gemv_static_vector_if<Scalar, OtherType::SizeAtCompileTime, OtherType::MaxSizeAtCompileTime, !UseOtherDirectly> static_other;

        ei_declare_aligned_stack_constructed_variable(
            Scalar, actualOtherPtr, other.size(), (UseOtherDirectly ? const_cast<Scalar*>(actualOther.data()) : static_other.data()));

        if (!UseOtherDirectly)
            Map<typename _ActualOtherType::PlainObject>(actualOtherPtr, actualOther.size()) = actualOther;

        selfadjoint_rank1_update<Scalar,
                                 Index,
                                 StorageOrder,
                                 UpLo,
                                 OtherBlasTraits::NeedToConjugate && NumTraits<Scalar>::IsComplex,
                                 (!OtherBlasTraits::NeedToConjugate) && NumTraits<Scalar>::IsComplex>::run(other.size(),
                                                                                                           mat.data(),
                                                                                                           mat.outerStride(),
                                                                                                           actualOtherPtr,
                                                                                                           actualOtherPtr,
                                                                                                           actualAlpha);
    }
};

template <typename MatrixType, typename OtherType, int UpLo> struct selfadjoint_product_selector<MatrixType, OtherType, UpLo, false>
{
    static void run(MatrixType& mat, const OtherType& other, const typename MatrixType::Scalar& alpha)
    {
        typedef typename MatrixType::Scalar Scalar;
        typedef internal::blas_traits<OtherType> OtherBlasTraits;
        typedef typename OtherBlasTraits::DirectLinearAccessType ActualOtherType;
        typedef typename internal::remove_all<ActualOtherType>::type _ActualOtherType;
        typename internal::add_const_on_value_type<ActualOtherType>::type actualOther = OtherBlasTraits::extract(other.derived());

        Scalar actualAlpha = alpha * OtherBlasTraits::extractScalarFactor(other.derived());

        enum
        {
            IsRowMajor = (internal::traits<MatrixType>::Flags & RowMajorBit) ? 1 : 0,
            OtherIsRowMajor = _ActualOtherType::Flags & RowMajorBit ? 1 : 0
        };

        Index size = mat.cols();
        Index depth = actualOther.cols();

        typedef internal::gemm_blocking_space<IsRowMajor ? RowMajor : ColMajor,
                                              Scalar,
                                              Scalar,
                                              MatrixType::MaxColsAtCompileTime,
                                              MatrixType::MaxColsAtCompileTime,
                                              _ActualOtherType::MaxColsAtCompileTime>
            BlockingType;

        BlockingType blocking(size, size, depth, 1, false);

        internal::general_matrix_matrix_triangular_product<Index,
                                                           Scalar,
                                                           OtherIsRowMajor ? RowMajor : ColMajor,
                                                           OtherBlasTraits::NeedToConjugate && NumTraits<Scalar>::IsComplex,
                                                           Scalar,
                                                           OtherIsRowMajor ? ColMajor : RowMajor,
                                                           (!OtherBlasTraits::NeedToConjugate) && NumTraits<Scalar>::IsComplex,
                                                           IsRowMajor ? RowMajor : ColMajor,
                                                           MatrixType::InnerStrideAtCompileTime,
                                                           UpLo>::run(size,
                                                                      depth,
                                                                      actualOther.data(),
                                                                      actualOther.outerStride(),
                                                                      actualOther.data(),
                                                                      actualOther.outerStride(),
                                                                      mat.data(),
                                                                      mat.innerStride(),
                                                                      mat.outerStride(),
                                                                      actualAlpha,
                                                                      blocking);
    }
};

// high level API

template <typename MatrixType, unsigned int UpLo>
template <typename DerivedU>
EIGEN_DEVICE_FUNC SelfAdjointView<MatrixType, UpLo>& SelfAdjointView<MatrixType, UpLo>::rankUpdate(const MatrixBase<DerivedU>& u, const Scalar& alpha)
{
    selfadjoint_product_selector<MatrixType, DerivedU, UpLo>::run(_expression().const_cast_derived(), u.derived(), alpha);

    return *this;
}

}  // end namespace Eigen

#endif  // EIGEN_SELFADJOINT_PRODUCT_H
